Low pressure intensifier for hydraulic press operation



Nov. 25, 1952 c, QUINN 2,618,930

LOW PRESSURE INTENSIFIER FOR HYDRAULIC PRESS OPERATION Filed July 7,1950 ll upum I mews/wax CL VE MALVIN qmm 2 M M r AGEN S Patented Nov.25, 1952 LOW PRESSURE INTENSIFIER FOR HYDRAULIC PRESS OPERATION CliveMalvin Quinn, Brighton, Victoria, Australia Application July 7, 1950,Serial No. 172,414 'In Australia July 14, 1949 Claims.

This invention relates to hydraulic presses employed for the moulding orforming of objects or articles from mouldable materials, such as, forinstance, plastics, or the bending or shaping of materials.

Hydraulic presses for production of moulded or formed articles, comprisein general, a cylinder, a ram fitting the cylinder and carrying a tableor movable platen whereon is mounted a mould section or die movable bythe ram and co-operating with a fixed mould section or die mounted onthe fixed platen or entablature of the press.

In order to charge the mould with material or locate a piece to beformed between the dies, it is necessary for the ram to have arelatively long stroke to separate the movable platen sufficiently fromthe fixed platen or entablature.

Hydraulic presses of the type indicated are commonly used in factoriesin association with a source of high pressure liquid for the manufactureof a variety of goods or articles, the high pressure liquid beingcommonly generated by powerdriven hydraulic pumps.

The principal object of this invention is to provide an effective systemfor operating a hydraulic press when motive fluid is available only at alow pressure, e. g., 100 lbs. per square inch, for the press operation.

A further object is to provide an efficient and comparativelyinexpensive apparatus whereby the operation of the press in accordancewith the invention may be carried out in practice.

In achieving the above stated principal object and accordin to theinvention, a method of operating a, hydraulic press of the typespecified consists in utilising a low pressure fluid to apply pressureto a press-operating liquid for impelling the ram at relatively fastrate against low resistance, and maintaining the pressure of said fluidupon the press-operating liquid so that upon increased resistanceopposing movement of the ram the pressure of said liquid isautomatically intensified to continue movement of the ram at lower speedagainst the increased resistance.

Conveniently, in thus actuating the press, the low pressure fluid isapplied to a relatively large area of a volume of the press-operatingliquid to supply the latter to the press cylinder at relatively lowpressure to impel the ram at the fast rate, and upon the ramencountering the increased resistance utilising the pressure exerted bythe low pressure fluid upon the relatively large area to apply adifferential pressure to a relatively smaller area of a separate volumeof the press-operating liquid to force the latter into the 2 presscylinder at intensified pressure to move the ram against the increasedresistance.

Theplaten or head of the ram may carry a movable mould or die sectionwherein or whereon the work to be moulded or shaped is placed and whichis co-operable with a fixed mould or die section supported on the fixedplaten or entablature of the press. In operation and under action of thelow pressure fluid the ram through the medium of the press-operatinliquid is actuated at comparatively high speed to close the mouldsections or engage the work on the movable die section with the fixeddie section. The resistance to movement thus imposed upon the ramautomatically elTects through the action of the low pressure fluid anintensification of pressure of the press-operating liquid whereby thetotal pressure or force upon the ram is greatly increased to completethe moulding or forming of an article or object.

The low pressure fluid may be air delivered by a compressed air service,or alternatively, water under low pressure from supply mains, the formerbeing preferable resultantly of its more rapid flow and speedy action.

In achieving the above recited further object of the invention, anapparatus for actuating a press by a low pressure service fluid,comprises cylinder charging means actuated by the low pressure fluid forsupplying the press-operating liquid to the press cylinder at lowpressure for moving the ram therein into mould or work engagement, andpressure intensifyin means operable by the low pressure fluid inresponse to mould or work engagement by the ram for increasing thepressure in the press cylinder to a high value to actuate the ram andcomplete a moulding or forming operation.

More specifically an apparatus for actuating a press by a low pressureservice fluid, comprises a chamber of large cross-sectional area, adisplacer in the chamber operable by the low pressure fluid, a chamberof small cross-sectional area associated with the chamber of largecross-sectional area and connected through valvular means with the presscylinder, a displacer in the large chamber having an extension withinthe smaller chamber, the space between the displacers being connectedthrough valvular means with the press cylinder and this space and thesmaller chamber containing press-operating liquid.

Upon admission of the service fluid to the larger chamber, the displaceroperable thereby is moved to expel operating liquid from the spacebetween the displacers into the press cylinder to move the ram thereinto engage the mould sections or dies in the press, a flow of operatingliquid from the press cylinder into the smaller chamber bein preventedby the valvular means.

Upon engagement of the movable and fixed mould sections or of the dieswith a workpiece, the resistance to movement of theiraman'dthe pressurein the cylinder increases. Thereupon,

the low pressure fluid automatically actuates both displacers, and theextension of the displacer within the smaller chamber resultantly of thedifferential areas of the latter and the larger chamoer, increases thepressure within the smaller chamber to a degree sufficiently great forthe completion of a moulded article or a formed piece. Upon the pressureincreasing to-the required extent the valvular means is operated toadmit the high pressure liquid from the smaller chamber to the presscylinder to complete the forming or moulding operation. The displacersmay comprise resiliently yieldable members deformable by the low"pressure fluid, or alternatively, rigid members movable bodily underthe action of the fluid.

I The accompanying drawing depicts one arrangementiof an apparatus foroperating a press of the type specified.

In this'drawing:

Fig. :l is a semi-diagrammatic view in section of the above apparatus.

1Fig.i2.is a section taken on lineZ-2 of Fig. 1.

Fig. 3is a section on the line 33 of Fig. ,2.

Thezapparatus consists of a cylindricalcasing ficlosed'at each end bythe cylindercoversor end plates I5 and l formingaclosedcylindricalzchamher .8. Secured to the'end plate '6 and coaxialwith the cylindrical casing 5 is a cylinder 9 of considerably reduceddiameter e. g. .6 toil-reducjtionin diameter, the cylinder 9 being openat the bottom and closed at the top by the "plate 7 It.

I'Disposed within the cylindrical chamber ii are .a'pair of resilientmembers Ii and I2 composed of rubber or like'sheets and preformed toassume an inverted cup shaped form in the operativeposition as viewed inFig. 1.

The :inner member I2 has a lesser mean diameterrelatively to the outermember I I- to thereby :provide a space therebetween forminga-recept-acle I3 for the reception of the press operating'1iquid,'inthis instance a suitable'oil.

The major diameter of each resilient member I I 'and' i2 is :such thatthe sidewall of the member Hand mouth of the inner member -I2 have adiameter approximately equal to the diameter of the wall- 5 of thechamber 8. The members II and: I 2'arerespectively formed withcircumferential marginal *rims it and I5 which .rims are clampedtogether between the flange 5a of the cylindrical'casing 5, and thelower end plate 1 by bolts la, as viewed in Fig. At approximatelythe'centrefihe end plate! is formed with aport Ma to "communicate'withthe pipeIEa which is connected toa source of compressed air. through thethree way-valve I6.

Therreceptacle 3 at :cneside is :arranged in communication with andconnected toapressure oil supply pipe .Il, extending to the hydraulicpressindicated generally at IS.

.Inorder to connect the pipe I? with'the'receptacle i3, a'relativelythick ring Ila. i clamped between the rims i i and I5 of the members IIand I2 by the bolts la and is formed with radial apertures I'Ib,seeF'ig. 3.

Secured to the ring i'ia by screws'tfl is a threaded aperture to whichthe pipe I! is screwed and accordingly connected by way of the apertureI'Ib with the receptacle IS. A check or nonreturn valve 2i is interposedin the pipe I! between the hydraulic press I9 and the casing 5.

Slidably fitting the chamber 8 and the small cylinder '9 is'a steppedpiston comprising a larger "disc-like section 22 fitting Within thechamber 8 and an integral trunk forming a ram 23 slidable within thecylinder 9.

A quantity of pressure oil is provided in the small cylinder 9 above theram 23, and is normally contained therein by the closure plate It. Acentral port 25 in the closure plate ID communicates with a pressure oilsupply pipe 26 .which communicates with the branch pipe 2'! through'thespring loaded non return valve 29.

The branch pipe 21 is connected at one end tothe oil pressure supplypipe I? above the nonreturn valve 2|, so that pressure liquid may passthrough pipe 26,.branch 27 and pipe I? into the hydraulic press 19..Beyond the junction of the .pipezz'a withthebranch pipe 2? a valve32isdis- .posed in the'latter.

In the positionshown in Fig. 1 the valve 32 will direct the flow ofpressure oil to the hydraulic press through the'branch pipe i'l theother end Zia of whichis connected tothe oil receptacleithrough anapertured plate pressure oil from the cylin'der dfrom passing into thereturn portion of the branch pipe 321. .The hydraulic press I9comprises; the cylinder- 38 containing a quantity of the pressure oilbetween the ram 39 fitting the cylinder and carrying a platenoriheadAll, upon which latter a-workpiece, die or'one section of a mouldmay be mounted to cooperate with a complementary part upon the'fixedplaten (not shown).

In operation the valve 56 is adjusted to the position shown wherebycompressed air enters the chamber IZafOrmed-by the'inner-member I2 which'-is expanded to therebyexert pressure upon and displace the oil in'thereceptacle I3-to flow into'the pipes I1 and 21. '-Thevalve33 preventsthe'displaced oil from passing up the'pipe 21 but the pressure issufiicient-to overcome theresistance of the spring associatedwith'valve2| whereby-the oil passes through" the. latter'into the cylinder 3B ofthe pressl9.

"The pressure of the ,oil' in the cylinder} 8 raises the ram 39 andplaten'M] towardsthefixed platen or -.entablatu1',e (not .shown) and.upon engagementbeing effected betweenthe mould Darts, dies or workpiece and diekresistance is setup to the movement of the, ram 39.and-resultantlyto the flowof oil .fromreceptacle I3 through the pipeI'ito the cylinder 38.

Continued pressure exerted by the; pressure lair upon the inner member I2. in the absence of-displacement of oil from the receptacle I3 causesthe expansion of the member I-2: and;resultant displacement of thepiston 22 and elevationof .the ram-23 in the small cylinder 9. The oilin the cylinder 9 is then forced pastthe .valve1'29, whichrequires agreater pressure than valve-ii to open, into and through the branch pipe21 to the pipe I! and cylinder 38 of the press.

The relative diameters of the piston 22 and ram 23 are such that thepressure applied to the oil in the cylinder 9 for transmission to thepress cylinder 38 responsive to the pressure applied to inner member i2,is such that the pressure is greatly intensified to move the ram 39 andplaten 40 at a relatively slower rate against the increasing resistanceset up by the operative engagement of the mould or die parts of the workpiece with the die.

The intensified pressure of the operating oil in the press cylinder 38achieves the completion of the moulding or die forming operationwhereupon the pressure and the operating oil may be relieved to permitthe ram 39 to return to the normal position. I i I To that end valve 32and valve l6 are adjusted, and this may be achieved simultaneously by'asimple dual control arrangement, whereby the air pressure is relievedfrom the inner elastic member l2 and exhausted through the valve l9 intothe branch [6a and atmosphere. Such a dual control arrangement for thesimultaneous actuation of the valves 32 and I6 may comprise an arm 4|operatively connected to the valve 32, an arm 42 equal in length to thearm 4| and operatively connected to the valve [6, a handle extention 43on the arm 4|, and a link 44 connecting the arms 4| and 42. It will beapparent that upon movement of the handle 43 and arm 4| through aquadrant, that is, an angular movement of 90, in the counter-clockwisedirection, as viewed in Fig. 1, from the position illlustrated, thevalve 32 will be moved to its fully open position for discharge of fiuidunder the weight of the ram 39, and the valve (6 will be moved to aposition shutting-off the supply of compressed air and simultaneouslyexhausting air from the chamber In through the pipe I5a and branch 16ato atmosphere. Simultaneously in the absence of the pressure exerted bythe elastic members H and I2 the oil flows through valve 32 into thereturn bend of the branch pipe 21 to pass into the return pipe 35, andthrough the valve 31 to refill .the small cylinder 9. Simultaneously aquantity of the oil is passing down the branch pipe 21 through the valve33 to re-enter the receptacle l3. Thus th oil initially displaced fromthe receptacle l3 and small cylinder is returned by the simpleexpediency of adjusting the two valves 32 and I6, the other valves beingopened responsive to the pressure of the oil flow.

In the practical arrangement above described resilient cup-shapedmembers II and I2 are used to form a compressible space or receptaclefor the press-operating liquid or oil, but it will be apparent that afloating piston may be fitted in the cylindrical casing and used inco-operation with the stepped piston or ram to charge the press cylinderwith operating liquid and intensify the pressure of the liquid for thecompletion of a moulding or pressing operation.

Iclaim:

1. A pressure intensifier for a hydraulic press comprising a receptacle,a first displacer in the receptacle movable by an operative fluid underpressure, valve means operable at will for admitting and exhausting theoperative fluid to and from the receptacle to control the movements ofsaid first displacer, a second displacer in the receptacle separatedfrom said first displacer to provide a space for a press-operatingliquid between said first and second displacers from which space thepress-operating liquid is forced at low pressure -for utilization in ahydraulic press in response to relative movement of said first andsecond displacers, a pressure-intensifying receptacle, and a thirddisplacer in the pressure-intensifying receptacle operatively connectedto said second displacer and movable by the latter in response toincreasing resistance to fiow oi press-operating liquid from said spacebetween said first and second displacers for supplying press-operatingliquid at high pressure from the pressure-intensifying receptacle to thehydraulic press.

2. A pressure intensifier for a hydraulic press comprising a casing, afirst displacer in the casing movable by a low pressure operative fluid,manually operable valve means for admitting and exhausting the operativefluid to and from the casing to control the movements of said firstdisplacer, a second displacer in said casing responsive to movements ofsaid first displacer and separated from the latter to provide a spacetherebetween for a relatively low pressure liquid, a high pressurechamber, a third displacer in said high pressure chamber connected toand operable by said second displacer to intensify the pressure of aliquid in said chamber, inlet tubular system means for supplying the lowpressure liquid from said space between said first and second displacersand the liquid under intensified pressure in said high pressure chamberto an hydraulic press, and tubular exhaust system means for returnin theliquid from the hydraulic press to said space and said high pressurechamber.

3. A pressure intensifier for a hydraulic press comprising a lowpressure cylinder, a first displacer in said cylinder movable by anoperative fluid under pressure, manually operated valve means foradmitting and exhausting the operative fluid to and from said cylinderto control the movements of said first displacer, a second displacer insaid cylinder responsive to movements of said first displacer andseparate from the latter to provide a space for a relatively lowpressure liquid between said first and second displacers, tubular meansfor conveying the low pressure liquid to a hydraulic press from saidspace between said first and second displacer an inlet valve in saidtubular means for controlling the admission of the low pressure liquidto the hydraulic press, a pressure-intensifying cylinder, a piston inthe pressure-intensifying cylinder operatively connected to said seconddisplacer, a tubular conduit for connecting the pressure-intensifyingcylinder with the hydraulic press, an inlet valve in said tubularconduit for controlling the admission of high pressure liquid from saidpressure intensifying cylinder to the hydraulic press, a tubular systemfor returning liquid from the hydraulic press to said pressureintensifying cylinder and said space between the displacers, and valvemeans in said tubular system for controlling the exhaust of liquid fromthe hydraulic press through said tubular system.

4. A pressure intensifier for a hydraulic press comprising a tubularcasing, a cover secured to each end of said casing, a first resilientdished member disposed at one end of said casing and defining conjointlywith the adjacent cover a receptacle for an operative fluid, apressure-intensifying cylinder on the cover at the opposite end of saidcasing, manually operable valve means for admitting and exhausting theoperative fluid to and from said receptacle to efiect expansive movementand permit contractive movement of saiidifirstxesilient :dished member,a second ire- .silient dished member, in the casing separated from-said:first dished member to provide a space for a press-operating liquidbetween the first and second dished members from which space thepress-operating liquid is forced at low pressure for utilization in a,hydraulic press in response to expensive movement of the first dishedmemcylinder and saidspace between'the dished mem- ..bers,-exhaust valvesin the exhaust tubular system, and amanually actuated valve in saidexhausttubular system operable to-connect said systems for discharge ofpress-operating liquid tosaid space and said cylinder.

5. A pressure intensifier for a hydraulic press comprising a cylinderflanged at each end, a cover secured to each ofv said end flanges, apair of elastic cupped members disposed in said cylinder onewithin-theother, peripheral rims on said cupped members clamped by'andbetween one of said covers and the adjacent flanged end 'o-fthecylinder, the inner cupped member defining with .said :one cover a;receptacle for compressed air and the outer cupped member beingseparated from said inner cupped member to define :a spaceforpress-operating liquid, a pressure intensifyingcylinderoi ,lessdiameter than the flanged cylinder :and mounted centrally on the other:cylinder .cover,;a pressure plate in said flanged within'said pressureintensifying cylinder, an inlet tubular system for connecting saidpressure-intensifying cylinder and said space for press-0per ating.liquid with a hydraulic press, valve inlet means in said inlet tubularsystem, an exhaust tubular system for connecting said inlet tubularsystem with said pressure-intensifying cylinder and said space betweenthe cupped members, valve exhaust means in said exhaust tubular system,a manually actuated valve in the exhaust tubular system operable toconnect said systems for :discharge of press-operating liquid to saidspace and said pressure intensifying cylinder, tubular means connectingsaid receptacle with a compressed air supply, and a three-Way valve insaid exhaust tubular system for controlling the supply and exhaust ofcompressed air to and from said receptacle.

CLIVE MALVIN QUINN.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,319,950 Schleicher et al. May25, 1943 2,351,872 Parker June 20, 1944 2,403,912 Doll July 16, 19462,511,541 Purcell June 13, 1950 2,569,226 Carter Sept. 25, 1951

